Method and apparatus for the production of screen-printing forms with a pattern having a motif repeated at least in the direction of the line

ABSTRACT

Scanning means scans a pattern area and the analog output signal thereof is converted to digital form. This digital signal is employed for causing an engraving means to produce a first pattern area on a screen printing form and is also employed through the intermediary of a writing means to provide output information on a magnetic storage means. Readout means associated with a storage means utilizes this output information to cause the engraving means to repeat the first pattern area on the screen printing form and the readout means is interconnected with the writing means to reproduce the output information on the storage means so that the pattern area can be reproduced a plurality of times on the screen-printing form.

United States Patent 1 1 1 3,597,532

[72] lnventors Ferdinand A. De Vos 56] References m Amsmi UNITED STATESPATENTS Jan H. Ter Steege, Abcoude, both of.

Nahum 2,832,064 4/1958 Lubkin 340/1 74.1 X (2 App, 775,783 3,107,34710/1963 Huss 179/1002 X Nov 1 CI al I [45] Patented, 3,1971 3,272,9189/1966 K011 et a1. 17816.6 [73] Assignee Werltspoor-Amsterdaln N-V-Primary Examiner-Terrell W. Fears Amsterdam, Netherhnds AssistantExaminer-Steven B. Pokotllow [32] Pr ori y w- L 1967 Attorney-[mine&'Smi1ey [33] Netherlands [31 67.16367 w w. a,

ABSTRACT: Scanning means scans a pattern area and the analog outputsignal thereof is converted to digital form. This digital signal isemployed for causing an engraving means to produce a first pattern areaon a screen printing form and is also employed through the intermediaryof a writing means to provide output information on a magnetic storagemeans.

[54] METHOD AND APPARATUS FOR THE PRODUCTION OF SCREEN-PRINTING FORMSWITH A PATTERN HAVING A MOTIF REPEATED AT LEAST IN THE DIRECTION OF THELINE 3cm": Dn'ingm Readout means associated with a storage meansutilizes this [52] [1.8. CI 178/6.6 B, output information to cause theengraving means to repeat the 178/6.6 A, 179/ 100.2 RE, 340/ 174.1 Pfirst pattern area on the screen printing form and the readout [51] Int.Cl. H04n 1/06, means is interconnected with the writing means toreproduce H04n 1/28, H04n 5/76 the output information on the storagemeans so that the pat- [50] Field of Search 178/6.6, 6.6 tern area canbe reproduced a plurality of times on the screen- B, 67, 6.6 A; 390/174.1 F; 179/1002 RE printing form.

METHOD AND APPARATUS FOR THE PRODUCTION OF SCREEN-PRINTING FORMS WITH APATTERN HAVING A MOTlllF IREIPEATED AT LEAST IN THE DIRECTION OF THELINE The invention relates to a method for the line-by-line preparationof screen printing forms with a pattern having a motif repeated at leastin the direction of the lines, by means of an electromagneticallycontrolled engraving member, photoelectric means for the line-by-linescanning of the pattern, and an electric circuit for converting theanalog signals received by the scanning means into discrete signalswhich are fed to a control circuit consisting of separate circuits forthe electromagnetic control, at different strengths, of the engravingmember, and apparatus for performing the method.

Photographic means are used in the prior art method for producing ascreen printing form with a pattern having a repeated motif. In thismethod the pattern is copied and the resulting photographic plates aredisposed on a plate or a roller of an engraving apparatus and scanned byphotoelectric means, the electric signals obtained being used to controlan engraving member which cuts the printing form.

A disadvantage of the prior art method is that photographic copying istime wasting and expensive; moreover, reproducibility is unsatisfactory,since each motif on the printing form is produced to a differentpattern. Apart from the faults caused by photographic copying, anotherdisadvantage is the variations in the scanning, which is alsophotoelectric.

It is an object of the invention to provide a method which obviatesthese disadvantages by enabling the motifs of the printing form to beproduced merely by the pattern being scanned once by the photoelectricscanning means.

To this end, according to the invention, use is made of a store which isdisposed in the connection between the scanning means and the controlcircuit for the engraving member and has a member for writinginformation into the store and a member for reading information out ofthe store, and the corresponding lines of the repeated motifs arewritten successively in a row extending in the direction of the lineinto the store and are again read out of the store, and the controlcircuit of the engraving member is operated without the intervention ofthe store for the engraving of the particular line of the first motif tobe produced on the printing form, and is operated with the interventionof the store for the engraving of the corresponding line of eachsubsequent motif, while the information fed to the writing-in member forthe first line ofthe row is supplied by the circuit between the scanningmeans and the engraving member and the information fed to the writing inmember for each subsequent line of the row is supplied by thereading-out member.

To this end, a line of the pattern is scanned once, these signals areused for controlling the engraving member, the signals also beingreceived in the store, and the engraving member for engraving theparticular line of the following motifs is controlled by the informationfrom the store.

A very satisfactory result is obtained if the analog informationreceived by the scanning means concerning the first line of theparticular row is fed, after conversion into discrete signals, to thewriting-in member of the store. By converting the information intodiscrete, for instance digital form, disturbances are avoided in readingout of the store and writing into the store.

The invention also relates to an engraving apparatus having anelectromagnetically controlled engraving member, photoelectric means, anelectric circuit for converting the analog signals received by thescanning means into discrete signals, and a control circuit which can beconnected to the conversion circuit and consists of separate circuitsfor the electromagnetic control, at different strengths, of theengraving member. An engraving apparatus of this kind is moreparticularly suitable for the performance of the method as set forth inclaim 2 if the apparatus has a store which is disposed between thescanning means and the control circuit for the engraving member and hasa member for writing information into the store and a member for readinginformation out of the store, the apparatus also having changeovermembers by means of which the control circuit of the engraving membercan be connected either to the scanning means or to the read ing-outmember of the store, and the writing-in member of the store can beconnected either to the: scanning means or to the reading-out member. Toobtain a satisfactory signal to noise ratio, the information concerningthe pattern is preferably written into the store in the form of digitalinformation. This can be done if the store is disposed? between thechangeover circuit and the control circuit for the engraving member.

The invention also relates to screen printing forms produced accordingto one of the methods described.

. An embodiment of the invention will now be described with reference tothe accompanying drawings, wherein:

FIG. I is a block circuit of an engraving member according to theinvention, and

FIG. 2 shows diagrammatically a disc store.

A pattern disposed on a roller I is scanned by photoelectric means 2,the resulting signals being fed to an analog-digital converter 3. Thediscrete signals produced by the converter 3 are converted in a codingmember 4 to a code word which can be fed, in dependence on the conditionof changeover means 5, either to a control circuit 6 for an engravingmember 7, or to a disc store 3, or to both. The information read out ofthe store can also be fed to the control circuit 6.

FIG. 2 shows diagrammatically a store disc 8. The angle A enclosed bythe radius connecting a reading-out head 10 to a pivot 11, and theradius connecting a writing-in head 12 to the pivot 11 can be manuallyadjusted and must correspond to the distance occupied by the patternalong the periphery of the scanning roller 1.

The reading-out head 10 and the writing head 12 can be electricallyconnected to one another by means of a switch 15. During the engravingofa line of the first motif to be produced on the printing form switch13 and switch 14 are closed, while switches 9 and 15 are open. For theengraving of the particular lines of the subsequent motifs, switches 13and 14 must be opened, while switches 9 and 15 are closed.

In this way a pattern scanned by the reading-out head 10 of the disc 8is fed to both the writing-in head 12 and the control circuit 6.Consequently, each pattern read out by the readingout head 10 is writtenin by the writing head 12 on the disc 8, so that when the disc hasrotated through an angle A in the direction shown by the arrow, thereading-0ut head 12 can again read the same information from the disc.

We claim:

1. Apparatus for preparing screen printing forms having successivelyrepetitive pattern areas, comprising in combination,

scanning means for scanning a pattern area and having an output relatedto the localized intensity of the pattern area as it is scanned,

engraving means for producing a first pattern area of varying localintensity on a screen printing form in response to the output of saidscanning means,

magnetic storage means,

writing means for writing into said storage means the output informationsupplied by said scanning means to said engraving means during saidproduction of the first pattern area,

readout means associated with said storage means arranged to encounterthe output information in .said storage means when the outputinformation concerning said first pattern area is completely writteninto said storage means,

and switch means for disconnecting said scanning means from saidengraving means and said writing means, and for connecting said readoutmeans to said engraving means and said writing means whereby a secondpattern area is produced by said engraving means from said outputinformation written into said storage means and said the outputinformation written into said storage means is in digital form.

3. Apparatus according to claim 2 wherein said storage means comprises aroller, said writing means and said readout means being spacedcircumferentially with respect to said roller.

1. Apparatus for preparing screen printing forms having successivelyrepetitive pattern areas, comprising in combination, scanning means forscanning a pattern area and having an output related to the localizedintensity of the pattern area as it is scanned, engraving means forproducing a first pattern area of varying local intensity on a screenprinting form in response to the output of said scanning means, magneticstorage means, writing means for writing into said storage means theoutput information supplied by said scanning means to said engravingmeans during said production of the first pattern area, readout meansassociated with said storage means arranged to encounter the outputinformation in said storage means when the output information concerningsaid first pattern area is completely written into said storage means,and switch means for disconnecting said scanning means from saidengraving means and said writing means, and for connecting said readoutmeans to said engraving means and said writing means whereby a secondpattern area is produced by said engraving means from said outputinformation written into said storage means and said output informationis reproduced in said storage means during said production of the secondpattern area.
 2. Apparatus according to claim 1 wherein scanning meansis a photosensitive device having an analog output signal varying inamplitude according to the localized intensity of the pattern area beingscanned and an analog-to-digital converter for converting said analogoutput signal to digital form whereby the output information writteninto said storage means is in digital form.
 3. Apparatus according toclaim 2 wherein said storage means comprises a roller, said writingmeans and said readout means being spaced circumferentially with respectto said roller.